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The production of ready-to-eat multi-component products undergone deep processing (culinary products, canned products, etc.) is an important direction in the development of the food industry. While manufacturing these products, it is necessary to maintain a balance of protein, fat and carbohydrate components. From a therapeutic and prophylactic point of view, the polyunsaturated fatty acids (PUFAs) of the ω-3 and ω-6 groups are significant components of the fat component. In order to increase the biological value of culinary products, technology has been developed for manufacturing new types of products using raw materials that are not traditional for similar classical products: cod liver, not sterilized, its fat and shark liver fat, which has a unique fatty acid composition. In the course of the study, shark fat and chilled cod liver, delivered to shore by fishing vessels, have been used as basic raw materials. The studies have been carried out using standard physicochemical and organoleptic methods. A technology has been developed for the manufacture of culinary products (salads, zrazy) using a microwave-processed semi-finished product of cod liver. Microwave treatment allows you to slow down the processes of hydrolysis of proteins and lipids due to the inactivation of tissue enzymes and the partial destruction of the autonomic micro-community containing proteases and lipases, which helps preserve the organoleptic and physicochemical characteristics of the raw materials. It has been established that the use of cod liver so blanched in the production of culinary products increases the nutritional value and quality of the finished product. The inclusion of shark fat in recipes also increases their biological value. This is evidenced by the results of studies conducted as part of the development of technology "Bulgarian bread". Evaluation of the finished product obtained by the developed technology has shown an increase in the biological value of the product "Bulgarian bread": the content of vitamin A – 38.8 % (5.31 % of daily requirement); PUFA – 13.9 % (7.15 % of daily requirement). The proposed technologies for the production of culinary products using unconventional fish oil raw materials will expand the range of multicomponent products.

The technology of high quality delicacy pasteurized canned foods from salmon fillets with the addition of exotic fruit and olive oil using heating temperature of less than 100 °C has been developed. The acceptable composition of marinade without common salt has been found experimentally. The sensory estimation mark of the product with this marinade formulation has reached 19.2 points on a 20 point scale. The most acceptable composition of canned salmon fillets with pineapple and olive oil characterized by a high content of salmon fillets has been determined (133 g from net weight 170, can 2). The results of preliminary heat engineering experiments using the complex Ellab TrackSense PRO (Denmark) have allowed to choose temperature-time mode of pasteurization of semi-canned foods packed in metal cans № 2 (net weight 170g): the duration of actual pasteurization is 60 minutes, the temperature is 85 °C. The practical lethality of the pasteurization mode is found to be 99.7 conditional minutes. Microbiological tests have shown that QMAFAnM before pasteurization is from 1.5 × 103 to 2.1 × 104 CFU/g which is less than normative values, while after pasteurization it is decreased to 5 × 101 CFU/g. The results of complex thermophysical, microbiological, and sensory researches have made it possible to clarify the pasteurization mode of the developed semi-canned foods. The microbiological stability of the developed semi-canned foods during 3-month storage at the temperature +3…5 °C and at the air humidity of 75 % has been proved. The chemical composition and energy value of developed canned foods has been found: total protein and lipid amount is more than 45 % of the product, the energy value is equal to 301 kcal. The content of selected fatty acids has been found, the monounsaturated fatty acids has been proved to be dominated in the lipids. The safety, high quality and food value of the developed delicacy semi-canned foods form the salmon fillets with addition of exotic fruit and olive oil have been proved.

The Baksan Underground Scintillation Telescope has been operating under the program of searching for neutrino bursts since the middle of 1980. The target is two parts of the facility with the total mass of 240 t. The actual observation time over the period from June 30, 1980, to December 31, 2016, is 31.27 years. No candidate for the stellar core collapse has been detected during the observation period. The upper bound for the mean rate of the supernova core collapse in our Galaxy is 0.074 y $$^{{ - 1}}$$ (90% CL).

An experiment for measuring the flux of cosmic gamma rays with energy above 100 TeV is currently being prepared at the Baksan Neutrino Observatory of the Institute for Nuclear Research, Russian Academy of Sciences. For this purpose, based on the Carpet-2 shower array which has been operating for many years, the Carpet-3 multipurpose shower array is being constructed. In particular, the preparation of the experiment supposes an increase in the area of the muon detector (MD) and ground part of the array. For ground modules of the Carpet-3 array, a scintillation detector with a liquid scintillator in a plastic package has been elaborated. In this work, descriptions of the Carpet-3 array and working characteristics of the new scintillation detector are presented.

An experiment for measuring the flux of diffuse cosmic gamma rays with energies above 100 TeV (the Carpet-3 experiment) is now being prepared at the Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences. The preparation of the experiment entails an increase in the area both of the muon detector and of the surface part of the air shower array. This work presents an estimate of the experiment sensitivity to showers generated by primary gamma quanta for different configurations of the array. According to experimental data of the Carpet-2 array for 9.2 years of pure data acquisition time, preliminary estimates for the upper limit of the diffuse cosmic gamma ray flux with energies above 930 PeV have been obtained.

The characteristics of fast neutrons produced by cosmic-ray muons at the Baksan Underground Scintillation Telescope (BUST) are investigated. A novel approach to the problem consists in estimating the neutron flux by the production rate of the unstable radioactive nuclide 12B in the (n, p) reaction on carbon nuclei of the BUST organic scintillator. The processing of the data collected in 2002–2015 yielded $${N_{{{12}_B}}} = 337 \pm 2.5$$ events consistent with those of the reaction 12C(n, p)12B. For the BUST internal planes, the background of fast neutrons with E > 28.6 MeV is experimentally estimated as Φ ∝ 10−11cm–2 s–1. This is lower than the theoretically predicted total neutron flux by nearly two orders of magnitude. The disagreement with predictions is attributed to the suppression of neutron flux in the external scintillator planes of the detector.

The new cosmic-ray experiment EMMA operates at the depth of 75 m (50 GeV cutoff energy for vertical muons; 210 m.w.e.) in the Pyhasalmi mine, Finland. The underground infrastructure consists of a network of eleven stations equipped with multi-layer, position-sensitive detectors. EMMA is designed for cosmic-ray composition studies around the energy range of the knee, i.e., for primary particles with energies between 1 and 10 PeV. In order to yield significant new results EMMA must be able to record data in the full configuration for about three years. The key to the success of the experiment is the performance of its tracking stations. In this paper we describe the layout of EMMA and construction of the two main detector types used for muon tracking: the high-resolution drift chambers and fast scintillation detector arrays. We also show the measured tracking efficiencies, position and angular resolutions, and sensitivity of drift chambers to the air pressure. The measured angular muon distributions are well reproduced by CORSIKA simulations folded with the known density distribution of the overburden. The single muon flux at the depth of 210 m.w.e. is (1.29 ± 0.06) m − 2 s − 1 . This value was determined from the reconstructed tracks registered by a six-layer array of position-sensitive drift chambers.

The fractional composition of proteins of the cod-fish family - polar cod ( Boreogadus saida ) and blue whiting ( Micromesistius poutassou ) which are currently underutilized in the food industry has been studied. A method of multiple extraction of homogenized fish raw material with solutions of increasing ionic strength and pH was used for protein fractionation. Water-soluble (WSP), salt-soluble (SSP) and alkaline-soluble (ASP) fractions of fish proteins have been separated. The content of protein in a whole fish and its aqueous extracts was determined by the Kjeldahl method as well as photometric method. The amino acid composition of the proteins was studied by high-performance liquid chromatography. Protein of blue whiting comprises 92% of WSP and SSP fractions; while polar cod comprisesonly 60%. All proteins under study contain the full set of the amino acids including essential ones. The content of lysine both in non-fractionated proteins contained in a whole fish and their fractions is considerable (from 59.5 to 121 g kg-1). When evaluating the biological value of proteins, their usefulness is established (there are no limiting amino acids). The data of the rationality coefficient Rc which presents the balance of the amino acid composition of the proteins indicate the high biological value of proteins of the whole polar cod and their ASP fraction. The fish species being studied can be used for production high-grade protein products - fish hydrolysates and isolates. The possibility of using unrefined fish is shown that is peculiarity of novel food technologies for obtaining protein products of high biological value.

The Baksan Underground Scintillation Telescope has operated within the program of searching for neutrino bursts since the mid-1980s. We present the current status of the experiment and some results related to the investigation of background events and the stability of facility operation. Over the period from June 30, 1980, to December 31, 2016, the pure observation time was 31.27 years. No neutrino burst candidate event from the explosion of a core-collapse supernova in the Galaxy was recorded in this time. This sets an upper bound of 0.074 yr–1 on the mean frequency of gravitational stellar collapses in the Galaxy at a 90% confidence level.

The MMIS-32 scaled multichannel measurement system, which is based on 32-channel charge-to-digital converters and has been developed and built, is described here. This system is intended for data acquisition from arrays of silicon photomultipliers used as multichannel photosensors in scintillation detectors. The basic parameters of the measurement system are presented.

An experiment for measuring the flux of cosmic diffuse gamma rays with energies above 100 TeV (the Carpet-3 air shower array) is now being prepared at the Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences. The preparations entail a substantial increase of the areas of both the muon detector and the surface air shower array. The experiment’s sensitivity to showers generated by primary gamma rays is estimated for different configurations of the array. In addition, preliminary estimates of the upper limit on the flux of diffuse gamma rays with energies higher than 1.3 PeV, derived using experimental data from the old Carpet-2 array, are presented for a net exposure time of 9.2 years.

Preliminary results of a neutron background measurement at the Baksan underground scintillation telescope (BUST) are presented. The external planes of the BUST are fully covered with standard scintillation detectors shielding the internal planes and suppressing thus background events due to cosmogenic and local radioactivity. The shielded internal planes were used as target for the neutron flux registration. The experimental method is based on the delayed coincidences between signals from any of the BUST counters. It is assumed that the first signal is due to inelastic interaction of a neutron with the organic scintillator, while the second signal comes from the decay of an unstable radioactive isotope formed when the fast neutron interacts with the 12C nuclei. Using the Monte-Carlo method (GEANT4) we also simulated propagation of neutrons through a layer of scintillator. The experimentally found muon induced neutron flux is j =1.3-0.3+0.7 ×10-10cm-2s-1 for neutron energies E ≥ 22MeV, which is in a qualitative agreement with similar measurements of other underground laboratories as well as with predictions of the GEANT4.

The current status of the experiment on recording neutrino bursts from core collapse stars is presented. The actual observational time is 29.76 years. An upper bound of the mean frequency of core collapse supernovae in our Galaxy is f col < 0.077 year–1 (90% CL).

The urgency of rational way of processing the offal of the Gadidae family (liver and gonads) for food purposes has been proved. The possibility of using the frozen gonads (milt and caviar) and the liver of the cod in the human nutrition (especially for the people of elderly age) has been researched. The frozen gonads with addition of fish liver are proven to be used for producing the canned foods with high quality level. The physical, chemical and microbiological characteristics of the product have been determined by the standardized methods. The quality level of canned foods has been obtained using the developed criteria of the objective evaluation of the quality. The specimens of the canned pastes produced from the frozen cod milt, caviar and liver using different compositions have been researched. Near-to-optimal composition of the new product has been defined. The quality level of canned food is 88.6 %. The commercial sterility of the canned food specimens prepared using the developed technology has been established. The chemical composition and the sensory characteristics of canned food have been researched. It has been established that protein content in the canned food is 12.9 %, fat content – 13.5 %, water content – 71.2 %, sodium chloride content – 1.3 %, carbohydrates content – 0.5 %. The product is the uniform, finely ground, evenly mixed mass with the presence of the separate caviar grains. The color of the paste is light-beige. The canned food has the tender consistency, pleasant taste and aroma. The energy value of the product is 678 kJ (162 kcal). Using the frozen cod caviar, milt and liver for producing the developed assortment of canned foods will make it possible to solve the problem of the complex processing of fish, and also to manufacture the canned food of high quality on the shore enterprises from the frozen fish offal (caviar, milt and liver) all the year round.

A way of estimating a muon-enduced neutron flux has been proposed. The technique is used to estimate the neutron background at the Baksan Underground Scintillation Telescope (BUST). A two-pulse signature (unstable 12B production and its subsequent decay) is used to identify neutron events. The integrated average neutron flux on the external planes of detector is an order of magnitude higher than the one on the internal planes. Within the limits of statistical error, the resulting neutron flux agrees with predictions from simulations for the depth at which the BUST lies using the FLUKA program.

A novel method for studying the hadronic component of extensive air showers (EAS) is proposed. The method is based on recording thermal neutrons accompanying EAS with en-detectors that are sensitive to two EAS components: an electromagnetic (e) component and a hadron component in the form of neutrons (n). In contrast to hadron calorimeters used in some arrays, the proposed method makes it possible to record the hadronic component over the whole area of the array. The efficiency of a prototype array that consists of 32 en-detectors was tested for a long time, and some parameters of the neutron EAS component were determined.

The technology of fish protein isolate from the low-cost raw material – the polar cod meat – was developed. The rationality of using partial alkaline-acid hydrolysis of minced fish for making fish protein isolate from the polar cod meat increasing the full-grade highly functional protein yield was proved. The most significant technological parameters influencing the physical and chemical characteristics of isolate were obtained; they are the parameters of washing and hydrolysis processes. The experiments of determination of the dependency of shelf life of the frozen raw material on physical and chemical characteristics of the raw material were carried out. The optimal quantity of washing cycles depending on the storage time was determined, it is 4 for the polar cod stored less than 4 month, and 6 for the polar cod stored more than 4 months. The dependency of temperature and pH of suspension changes during hydrolysis on the most significant quality characteristics (protein content, isolate yield by minced fish, isolate soluability)was obtained. The optimal values of these factors are: the temperature of 98 ˚С, pH of 11.75. The technology of manufacturing cholesterol-free mayonnaise choosing the fish protein isolate as an emulsifier was developed. The high emulsifying ability of fish protein isolate in fine emulsion “oil in water” was proved: increasing the content of isolate by 0.6 % the emulsifying ability increases by 1.85 %. The organ, oleptic microbiological, physical and chemical analyses of the mayonnaise were carried out, the recommended shelf life (30 days at the temperature from 3 to 5 ˚С) was found. The fish protein isolate was also used for meat and fish frankfurters. The receipt of these frankfurters includes pork, FPI, microwave-blanched cod liver, salt, species, sugar, tomato paste, potato sctarch and yolk, liquid smoke.

The search for muon neutrinos with energy ≥1 GeV correlated with Gamma-Ray Bursts (GRBs) has been carried out at the Baksan Underground Scintillation Telescope (BUST). Between 1978 December and 2013 December more than 1500 localized gamma-ray bursts occurred in the field of view of the BUST were coincided with the BUST operation periods. No neutrino signal from GRBs was detected. Upper limits on associated gamma-ray burst neutrino production are presented.

The origin of gamma-ray bursts is still one of the unresolved problems in physics. They are short, intense, and non-repeating flashes of MeV gamma-rays with a wide range of spectral and temporal properties. Also these bursts are perhaps sources of neutrino emission. Unlike the photons, which may scatter or be absorbed, the neutrinos, due to their small interaction cross section, arrive at the Earth unaffected. This paper describes experimental methods for detection of low energy neutrinos in the range from 20 MeV to 100MeV at the Baksan Underground Scintillation Telescope. In the analysis we search neutrinos in time coincidence with a gamma-ray burst. We use filtered data collected at the Telescope during 2012. We also use the catalogue of gamma-ray bursts of the SWIFT satellite experiment.

The current status of the experiment on recording neutrino bursts is presented. As the target, we use two parts of the facility with the total mass of 240 tons. Over the period of June 30, 1980 to December 31, 2016, the actual observational time is 31.27 years. No candidate for the stellar core collapse has been detected during the observation period. An upper bound of the mean frequency of core collapse supernovae in our Galaxy is f < 0.074 per year (90% CL).

An experiment for measuring the flux of gamma rays of cosmic origin with energy above 100 TeV (the Carpet-3 experiment) is currently being prepared at the Baksan Neutrino Observatory. The experimental setup suggests substantial increase of the areas of both muon detector and surface air shower array. We present some results of calculations of selection efficiency of air showers from primary gamma rays for different configurations of the array. It is demonstrated that by increasing the muon detector area up to 615 m$^2$ (the maximum possible value) one can reach with the Carpet-3 the world-best sensitivity to 100 TeV gamma rays. The preliminary values of upper limits on the flux of cosmic diffuse gamma rays with energy higher than 930 TeV are also presented, derived from experimental data of the Carpet-2 shower array for a net exposure time of 9.2 years.

The results from a 29-month investigation into the EAS electromagnetic component using the PRISMA-32 array are presented, notably for the central density spectrum and energy deposit spectrum. The array consists of 32 en-detectors in which specialized inorganic scintillators (SL6-5 phosphorus composition) based on silver-activated zinc sulfide (ZnS) with LiF enriched to 90% 6Li (ZnS(Ag) + 6LiF) are used as detecting layers. The possibility of detecting the electromagnetic component using a thin scintillation neutron detector with the multiple passage of charged particles is shown. The experimental data are compared to the results from simulations.

The matrices formed of silicon photomultipliers (SiPMs) are very promising photosensors for the scintillation detectors. The use of SiPM matrices with appropriate optical collector gives, in principle, a possibility to do a snapshot of glowing track of charged particle traversing a scintillator. The prototype of such scintillation detector is under development now in INR RAS. The preliminary results of characterization study of the matrix ArrayC-60035-64P-PCB (SensL company) for the prototype of such detector are presented., Poster contribution to the International Conference on New Photo-detectors (July 6-9, 2015, Moscow, Troitsk, Russia), to be published in PoS (PhotoDet2015)

The results of a characterization study of the scintillation detector with SiPM matrices as multichannel photosensors are presented. The SiPM matrix attached to a plastic scintillator gives a snapshot of the glowing track of a charged particle traversing the scintillator.

A method is proposed for automatic tuning and stabilization of the energy threshold in scintillation detectors by maintaining the constancy of the average detector counting rate from Γ rays of natural radiation background or cosmic rays. Stabilization is automatically performed by controlling the photodetector supply voltage, which makes it possible to stabilize the detector threshold with an error of 0.73–2.40%, depending on the used circuitry. The stabilization electronics for scintillation detectors with avalanche multipixel photodiodes and photomultipliers is described. A circuit ensuring the increased precision of threshold stabilization is also proposed.

The current status of the experiment on recording neutrino bursts from core collapse stars is presented. The actual observational time T (from June 30, 1980 until December 31, 2009) is 25.58 years. An upper bound of the mean frequency of gravitational collapse in our Galaxy fcol < 0.090 year−1 at a 90% confidence level. The results of studying single events at the facility in the case of muon inelastic interaction of cosmic rays with the matter of the detector are presented.

Characteristics of the hadronic component of exstensive air shower (EAS) trunks are investigated at the CARPET-2 array of the Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences. In this work, we study showers with axes that located within its muon detector (MD). We discuss the procedure for selecting such showers in our experiment. The relationship between the number of thermal neutrons detected by heat detectors installed in the muon detector’s tunnel and the total energy of a cascade generated by hadrons in the magnetic detector’s absorbent matter is presented.

The energy spectra and temporal characteristics of high-energy gamma-ray bursts from evaporating primordial black holes have been calculated using various evaporation models. The currently existing theoretical uncertainties in the shape of the evaporated photon spectrum are discussed. The data from the Andyrchy and Carpet-2 arrays of the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) obtained in the mode of detection of a single cosmic-ray component are used to search for cosmic gamma-ray bursts with a primary photon energy of about 8 GeV. New upper limits have been obtained for the number density of evaporating black holes in a local region of space with a characteristic size of ∼10−3 pc for various evaporation models.

The first results of measurements of the thermal-neutron flux in extensive air showers (EASs) using an unshielded scintillation thermal-neutron detector in the Multicom prototype array at the Baksan Neutrino Observatory of the Institute for Nuclear Research are reported. The operating capacity of the new method for studying the EAS hadron component via detection of thermal neutrons and good prospects of this method are demonstrated.

The Andyrchy facility was created for studying the energy spectrum and nuclear composition of primary cosmic rays in the region of a knee in the cosmic-ray spectrum. The position of this facility above the Baksan underground scintillation telescope allows simultaneous detection of electron-photon and high-energy muon components of extensive air showers. The parameters of this facility also allow it to be used for solving a number of other problems of cosmic-ray physics. Data since 1996 have been collected for several physical problems. The facility is described, and its performance characteristics are presented.

A procedure for measuring energy releases in scintillation detectors by using a logarithmic RC converter in combination with a device that suppresses photomultiplier tube afterpulses is described. The total range of measured energies is 5.8 MeV to 11.6 GeV. The afterpulse suppression ratio is more than 200. The output pulse of the RC converter is synchronized with the leading edge of the anode signal from the photomultiplier tube.

Two circuits of wide-range converters of the dynode current amplitude of photomultiplier tubes (PMTs) into duration are presented. They are intended for measuring the energy released in large scintillation detectors. The first-type converter has a protective switch at the input, which eliminates the influence of PMT afterpulses on the conversion process. The second-type converter is weakly sensitive to PMT afterpulses, and its output pulse is synchronized with the leading edge of the input signal. Both devices have a dynamic range of 2 × 103.

A new data acquisition system that makes it possible to measure the count rate of each detector of the Andyrchi air shower array every millisecond is described. This new detection system allows us to search for ultrashort bursts of cosmic ray intensity when operating the array in the single-component detection mode. The method of data acquisition and analysis is discussed.

The prototype of a novel type EAS (extensive air shower) recording and investigation array (the PRISMA project) is created on the basis of the NEVOD experimental complex through cooperation between Institute for Nuclear Research, Russian Academy of Sciences, and the National Research Nuclear University MEPhI. The prototype (ProtoPRISMA) consists of thirty-two en-detectors sensitive to EAS electromagnetic (e) and hadronic (via the registration of thermal neutrons) (n) components. The array is designed to develop and to test a new method of EAS investigation using neutron and electromagnetic components and to obtain preliminary data on the spectrum and composition of cosmic rays.

The system of anti-lightning protection measures set up under the high mountain conditions of the Andyrchi facility at the Baksan Neutrino Observatory of the RAS INR is described. A number of practical recommendations for the anti-lightning protection of the electronic equipment at physics installations that have long lines of communication between their physical quantity sensors and recording instruments are given.

At present an experiment for measuring the flux of cosmic diffuse gamma rays with energy higher than 100 TeV (experiment "Carpet-3") is being prepared at the Baksan Neutrino Observatory of the Institute for Nuclear Research, Russian Academy of Sciences. The preparation of the experiment implies considerable enlargement of the area of both muon detector and surface part of the shower array. At the moment the plastic scintillation counters with a total continuous area of 410 m2 are installed in the muon detector (MD) underground tunnels, and they are totally equipped with electronics. Adjusting of the counters and their electronic circuits is in progress. Six modules of shower detectors (out of twenty planned to be installed) have already been placed on the surface of the MD absorber. A new liquid scintillation detector is developed for modules of the ground –surface part of the array, whose characteristics are presented. It is shown that the "Carpet-3" air shower array will have the best sensitivity to the flux of primary gamma rays with energies in the range 100TeV – 1PeV, being quite competitive in gamma-ray astronomy at such energies.

The project of the Baksan Underground Scintil- lation Telescope (BUST) upgrade is presented. Additional outer layers of the detectors with fine spatial resolution will be mounted around BUST. Optimal dimensions of a counter, 0.125m◊ 0.125m◊ 0.03m were chosen with a simulation program. The functional diagram of BUSTs DAQ additional layers is presented. Modernization allows us to study the knee region using muon number spectrum measurements. BUST located underground at a depth of 850 m of wa- ter equivalent was designed to solve a number of physical problems which predetermined its construction and location (Alekseev et al., 1998). The telescope is a four-store building with dimensions of 16.7m◊ 16.7m◊ 11.1m and consists of four horizontal and four vertical planes. The total number of detectors is 3180. The analysis of the muon groups registered by BUST gives us an opportunity to obtain information about spectrum and composition of primary cosmic rays in the energy range of 1013 1016 eV (Petkov et al., 2008). The coordinates of fired detectors give the initial information for identification parameters of muon groups (arrival direction and number of muon tracks). In general, the number of muons cross- ing the telescope, n, and the number of the reconstructed muon tracks in a selected event, ntr, should not necessar- ily coincide with each other. When two or more muons are crossing BUST close enough to each other (comparable with the size of the detector), the number of reconstructed muon tracks will be less than the number of muons crossing BUST. Construction of additional external scintillation layers pro

An innovative method for studying the properties of extensive air showers (EASes) that is based on the detection of thermal neutrons generated by high energy hadrons under a soil absorber of 500 g cm−2 is proposed and tested. It is shown that underground hadronic calorimeter can be performed with special scintillation detectors developed by the authors. The method could be quite useful in gamma shower selection and investigations of EAS properties, primary cosmic ray mass composition, EAS core location, and so on.

In this short note we present results of background measurements carried out with polystyrene based cast plastic 12.0×12.0×3.0 cm3 size scintillator counter with a wavelength shifting fibre and a multi-pixel Geiger mode avalanche photodiode readout in the Baksan underground laboratory at a depth of 200 metres of water equivalent. The total counting rate of the scintillator counter measured at this depth and at a threshold corresponding to ∼0.37 of a minimum ionizing particle is approximately 1.3 Hz.

The first experimental data on detection of thermal neutrons accompanying extensive air showers (EASs) which were obtained at two prototypes of the future novel PRISMA EAS array are reported. The operation of this array (even in the minimum prototype version) and its ability to yield completely new information on the hadron and electron components of the EAS were experimentally checked.

The first results obtained during one year of measurements at the upgraded shower Carpet-2 installation at the Baksan Neutrino Observatory of the Institute for Nuclear Research, Russian Academy of Sciences, are presented. The results of calculation of the energy response of the installation are given. The results of data analysis using the standard method and the East-West method are compared. The constraints on amplitudes of harmonics of solar anisotropy for three values of primary energy: E > 12 TeV, E > 40 TeV, and E > 70 TeV, are obtained.

The state of the art and the project of modernization of the extensive-air-shower array Carpet-2 of the Baksan Neutrino Observatory of the Institute for Nuclear Research, Russian Academy of Sciences are described. The modernized array will allow the performance of detailed study of variations in the cosmic ray intensity, the energy spectra and composition of primary cosmic rays in the energy range 1013–1016 eV, and the anisotropy of primary cosmic rays with energies above 1013 eV.